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Kostic, A., Kremic, M., Djokic, L., & Kostic, M. (2013). Light-emitting diodes in street and roadway lighting – a case study involving mesopic effects. Lighting Research and Technology, 45(2), 217–229.
Abstract: The paper considers the justification for the application of light-emitting diode (LED) technology to urban lighting. The results suggest that LEDs are convenient for architectural lighting and deserve to be considered for use in ambient lighting. The recently developed Commission Internationale de l’Eclairage (CIE) mesopic system enabled the inclusion of mesopic effects into a comprehensive techno-economic analysis, which dealt with efficiency, maintenance and financial aspects of the use of LEDs in street and roadway lighting. It is concluded that the average energy savings when using LED instead of high-pressure sodium (HPS) luminaires amount to 19–26% for single-sided, staggered and opposite layouts, although they are frequently negligible if mesopic effects are not included. The total costs of the LED lighting solutions, even including mesopic effects, are 1.36 to 6.44 times higher than those of the comparable HPS lighting solutions. Therefore, LEDs are questionable for street and roadway lighting.
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Kuhn, L., Johansson, M., Laike, T., & Goven, T. (2013). Residents' perceptions following retrofitting of residential area outdoor lighting with LEDs. Lighting Research and Technology, 45(5), 568–584.
Abstract: The use of light emitting diodes (LEDs) in outdoor lighting has energy-saving potential, but users’ responses to this light source are largely unknown. An intervention study in two residential areas compared conventional lighting installations (high pressure sodium in Area 1 and high pressure mercury in Area 2) to a retrofitted LED-alternative regarding residents’ perceptions of quality of light, visual accessibility and danger. Moreover, energy use was calculated. Residents’ (N = 60) visual accessibility improved and perceived danger remained low in both areas after retrofitting. In Area 2 the perceived quality of light increased, whereas in Area 1 the results were mixed. The retrofitted application reduced energy use by 41–76% and might be a feasible alternative to conventional outdoor lighting in relatively safe areas.
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Kyba, C. C. M., Hänel, A., & Hölker, F. (2014). Redefining efficiency for outdoor lighting. Energy Environ. Sci., 7(6), 1806.
Abstract: Improvements in the luminous efficiency of outdoor lamps might not result in energy savings or reductions in greenhouse gas emissions. The reason for this is a rebound effect: when light becomes cheaper, many users will increase illumination, and some previously unlit areas may become lit. We present three policy recommendations that work together to guarantee major energy reductions in street lighting systems. First, taking advantage of new technologies to use light only when and where it is needed. Second, defining maximum permitted illuminances for roadway lighting. Third, defining street lighting system efficiency in terms of kilowatt hours per kilometer per year. Adoption of these policies would not only save energy, but would greatly reduce the amount of light pollution produced by cities. The goal of lighting policy should be to provide the light needed for any given task while minimizing both the energy use and negative environmental side effects of the light.
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Mathews, F., Roche, N., Aughney, T., Jones, N., Day, J., Baker, J., et al. (2015). Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland. Philos Trans R Soc Lond B Biol Sci, 370, 20140124.
Abstract: Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements—both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts—bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered ‘light-attracted’ and likely to benefit from the insect congregations that form at lights. Leisler's bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability.
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Nasar, J. L., & Bokharaei, S. (2017). Impressions of Lighting in Public Squares After Dark. Env. & Behav., 43(3), 227–254.
Abstract: Lighting may affect impressions of public squares. Following studies on office interior lighting, the present research manipulated three modes of lighting—non-uniform–uniform, peripheral–overhead, and dim–bright—in three virtual squares. One study had 32 participants (15 men, 17 women) judge the spaciousness and privacy of each of the 24 public squares. A second study had a different group of 30 participants (16 men, 14 women) rate the appeal, safety from crime, and excitement of each square. Study 1 found that judged spaciousness increased with uniform and bright lighting, and that privacy increased with non-uniform, dim, and peripheral lighting. Study 2 found that rated appeal increased with uniform and bright lighting, as did safety from crime and excitement. Across the two studies, the uniform and bright lighting conditions contributed most to the kinds of favorable experiences people might expect to have in public spaces after dark.
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